Targeted investment in relining, either through spray liner systems or through CIPP (cured in place pipe lining) provides a cost-effective method of extending the lifespan of buried infrastructure while reducing the risk of bursts and discolouration incidents.
Additionally, extending the usable life of existing assets and focusing on trenchless technology reduces environmental impact and embedded CO₂ in comparison to traditional replacement solutions.
Customer benefits can also be gained by reducing the duration of any remedial works, minimising impact, especially when working in major urban areas.
The correct preparation method is essential for successful relining that delivers true long-term performance.
Without adequate preparation, early failures of the lining can occur, resulting in repeated investment, reactive operational response to manage any customer disruption and customer contacts that come with any unplanned variations in supply.
We are supporting targeted relining investment through a strategic partnership with Canadian firm Envirologics. The Tomahawk™ System uses a patented high vacuum low-pressure airstream to draw abrasives through pipework, removing tuberculation, biofilms, old bitumen or coal tar linings. The preparation process is viewed live using the Tomahawk™ Scout camera system allowing the preparation team to provide assurance to the client that the works are completed to the correct standard.
In this article, we describe the current UK standard for mains preparation (IGN 4-02-02), and how the Tomahawk™ System meets these requirements to provide best-in-class surface preparation for superior bond and long-term, leak-free performance.
The key elements to consider when preparing the internal surfaces of a pipeline are:
• Consistent and thorough coverage.
• Access to difficult areas such as service connections.
• Dry, clean, dust-free substrate.
• Assurance of the elements above have been satisfied.
When we evaluated the Tomahawk™ System we ensured these aspects were met, additionally the system had to meet our requirement to deliver the solution that was:
• Cost effective across whole asset life.
• Supportive for rapid return to service.
The current IGN 4-02-02 gives guidance on preparation ahead of spray lining products such as the popular 3M Scotchkote Liner 2400 and 2100 and states:
- Prior to spray application of any resin material, the main shall be free from standing water.
- The quality of cleaning is paramount if coatings are to be applied successfully. The cleaning method employed shall leave the bore of the pipe free of tuberculation, deposits and loose or deteriorated remains of original coatings.
- Lining through standing water is regarded as severe water damage and the main shall not be returned to service until the fault has been rectified to the satisfaction of the Utility Representative.
From our assessment, although existing methods for preparation can address some of the requirements we feel that the Tomahawk™ System offers a distinct advantage in three key areas.
Ensuring a dry substrate
The Tomahawk™ System uses patented technology to draw abrasives through the pipework in a high vacuum low-pressure airstream, it is the only system to able to employ this method, and by drawing the abrasives through and out of the pipework it also removes all dust, removed tubercules, debris and moisture from the main pipe section. It also uses targeted cleaning to generate a “Vaculation” effect to remove moisture from service connections and pipe joint inverts, other methods can leave these containing moisture, and during the delay between preparation and relining this moisture can re-enter the pipe body thus breaking the bond between pipe and liner leading to future failures.
Access to difficult areas
Working in a trenchless environment means remote access to the point of need. Traditional methods cannot actively target areas of specific need during the preparation process, this results in high levels of preparation on the easy to reach areas such as the main pipe wall only. Difficult and obscured areas such as behind service intrusions can be missed. By using their patented Tomahawk™ Scout (a specialist camera system) as an integral part of the preparation process the abrasives are deflected into these areas that would be missed by traditional scraping methods, or by other abrasive means.
The inclusion of the Tomahawk™ Scout is also key in providing assurance around consistent coverage while protecting project cost duration. The preparation works are monitored live by the operators to ensure all areas are cleaned back to the required IGN 4-02-02 standard.
Click here to see the Tomahawk™ System in action
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